Posted
by
timothy
on Sunday October 04, 2015 @03:17PM
from the gentleman-hit-your-buttons dept.

Ars Technica takes an in-depth look at some of the tech side of the hybrid racing circuit, in particular the World Endurance Championship . From the article: Hybrid systems are allowed to deploy between 2MJ and 8MJ of energy during a single lap of Le Mans, augmenting the power from an internal combustion engine. Energy can be recovered from up to two motor/generator units (MGUs); usually this means recapturing kinetic energy from the front and rear wheels under braking. To balance things out, cars that recover and deploy 8MJ carry less fuel, and the flow rate at which they can feed it to the engine decreases.
Audi's R18, with its mix of turbo diesel and flywheel hybrid technology, was king of the hill for several years, but the hybrid systems were much less powerful. Last year, Toyota's gasoline V8 and supercapacitor-powered TS040 was the car to beat. But 2015 is the year of the Porsche 919 Hybrid. Porsche chose lithium-ion batteries to hybridize the 919's turbocharged gasoline V4, and this year is able to capture and deploy the full 8MJ (Toyota is in the 6MJ class and Audi 4MJ).
The article spends more space on Audi's approach than the others, but offers a cool glimpse at all three of these companies' niches within the field, as represented at the Texas' Lone Star Le Mans.

... that F1 cars are hybrids these days? Apparently not. They use systems that are referred to as "KERS". In fact, according to this article, [wikipedia.org] the Audi Le Mans car uses a hybrid system originally developed by an F1 team.

There is nothing else like it anywhere. Oh yes, there are moto races that are longer and "less boring" to the NASCAR crowd, but if you pay attention for even 5 minutes to this race, you will be hooked like I was.

Actually KERS (Kinetic Energy Recovery System) is old rules, nowadays they have an MGU-K (Motor Generator Unit - Kinetic) harvesting under breaking and a MGU-H (-Heat) which harvests from the turbo when it has excess spin and can also keep the turbo spooled up. https://en.wikipedia.org/wiki/... [wikipedia.org]

One lap of Circuit de la Sarthe is 13.629 kilometres, and has several long straights, and relatively few turns for its length, so the energy harvesting is more difficult than most people would expect, which is what helps make these cars even more impressive than the admittedly impressive on their own right F1 Power Units.

The most impressive thing with the LMP1-H cars is the reliability of the systems. Given the fact that for the last 15 years or so of WEC and its predecessors in sportscar prototype racing, if you really want to have a chance of winning at Le Mans, you can't afford to tune down the engine for reliability, as was standard practice in the 80's and through most of the 90's. Nowadays, the systems are tuned the same for 24 hour races as they are for 6 hour races: All-out.

Engine repairs or swap-outs are not allowed during races, which makes the fact that they survive 5k+ km in 24 hours